If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Along with Guido's PTH waveguides, a new pair of 2431H drivers came in. I mounted them in the modified L200's on PTF waveguides. No EQ, just the AM crossovers we're using, here's the performance, L & R:

- Nice matched set of drivers .

- I'd like to see what they can do on a 650 hz horn with a low crossover point . Do you have any horns like that ?

- A quick suggestion ; I just spent about 10 minutes using the search engine to try to find ( within this thread ) the technical info that relates to your "AM" crossover reference . Maybe for the rest of us, you could note what post that info is found in so we can follow along . Thanks !

"AM" crossover refers to HF section of AM6212/00, the JBL product which uses the 2431H on PTH (12" X 12" square) waveguides, but in combination with the LF section of 4430's N3134. Guido's building with 4435's N3135 LF.

- Thanks for the AM update. I'll take a look at all that info this weekend .

- Now that you've established the HF capabilities of the 243x series / I would love to see just what it can do in the lower regions .

- One of the reasons I published those RTA pics of the B&C 900 / RCA horn was to demonstrate just how much lower midrange can be obtained when a large horn is used. By the way ; The cut sheet on that driver actually recommends a 1200 hz point ( at 12 db / octave ).

- Considering the 2431s' top end extension , I'd love to see what those 2431Hs are capable of on the H9800 . That would be a reasonable test / even with the tight back-cap . How about you and the Widget hooking up sometime in the future to suss this out ( or is the H9800 travelling ? ) Anyways

Work in progress:

1) DIY crossovers, nearly complete, await delivery of a few coils from Parts Express. N3134's (top) incorporate full original switching plus Zilch's new "Biwire" option using available 6th switch pole. AM version (bottom) for upgraded L200's is way simpler.

2) Switches for N3134 are prewired using 18 Ga. (16/30) hookup wire; 12 leads total required. They made construction a decidedly non-trivial endeavor. I had to break out the magnifying visor to build them, and it took over an hour apiece to do it. Wire colors denote six different switch functions, so the Zilchster gets the connections right.

3) Rear of N3134's prior to switch installation (bottom) and after (top). Bifurcated terminal ends (see unwired ones there) permit secure point-to-point wiring. Components are laid out to simplify it and minimize lead crossings, as if it were a printed circuit. 1/8" thick electrical-grade fiberglass substrate will mount on recessed rear panel per JBL convention. Boards are 7" square.

The input terminals used here are REdiculous. They'll accommodate lead wires the diameter of a pencil.

L200 Grilles

Sonofagun's L200 grilles arrived today. Not glued to screens yet, they're just sittin' there lookin' like a million bucks! RTA finds them to be acoustically transparent.

While the texture is different, of course, the color is a close match to JBL Monitor Blue. Look closely at the closeup pic, and you'll see there's a swatch of factory grille cloth stuck on there for comparison.

Do we know the JBL Part# of those little plastic pinback logos? It'd be good to save forum members the embarassment of paying $25+ for them from the Orange County reconer guys....

Do we know the JBL Part# of those little plastic pinback logos? It'd be good to save forum members the embarassment of paying $25+ for them from the Orange County reconer guys....

I have a pair of the original metal logos that are appropriate to the L100 and L200 among other JBLs of the era... If there were a number of members interested in them I could do a run of 20+ and they should be about $5 ea. maybe less.

I've received several inquiries regarding my crossover construction method illustrated above. The push-in terminals I'm using were discontinued and the tooling destroyed 30 years ago. I only have enough stock for my own use presently.

BUT, I'm trying to round up more from surplus and grey-market sources right now. If there's enough interest, I'll consider making new tooling to produce them....